Desiccant end cap

ABSTRACT

A desiccant end cap for mounting on a hollow cylindrical member having an annular flange with a face portion and an outer annular portion extending transversely thereto comprising a cup-like member having an end portion and an annular rim extending substantially perpendicularly to the end portion for overlying said outer portion of said flange with an interference fit, desiccant container means mounted centrally on said end portion for positioning within said hollow tubular member, spacer dimples on the end portion of said cap for positioning said end portion in spaced relationship to the face portion of the flange, and latching dimples on said rim for engaging said flange with a holding fit.

United States Patent 1191 Cullen et al. C

1 Nov. 11, 1975 DESICCANT END CAP [73] Assignee: Multiform DesiccantProducts, Inc.,

Buffalo, NY.

Primary E.\umiI1erGeorge E. Lowrance Attorney, Agent, or Firm-Joseph P.Gastel [57] ABSTRACT [22] Filed; Ap 1, 1974 A desiccant end cap formounting on a hollow cylindrical member having an annular flange with aface [21] Appl' 4361,90 portion and an outer annular portion extendingtransversely thereto comprising a cup-like member having [52] US. Cl206/204; 312/31 1 an end Portion and an annular Tim extending Substan-[51 rm. c1. 13651) 81/24 tinlly perpendicularly to the end Portion foroverlying [58] Field of Search 206/204; 312/31, 31.1 Said Outer portionof Said flange with an interference fit. desiccant container meansmounted centrally on [56] References Cit d said end portion forpositioning within said hollow tu- UNITED STATES PATENTS bular member,spacer dimples on the end portion of 7 53] 084 l l H 950 S 7 2 said capfor positioning said end portion in spaced re- Q M951 83? lationship tothe face portion of the flange, and latch- 2:676:1171; 4/1951yongiiiiiji iiiijiijjjii: 515/31, ne dimple on end nm for engaging saidflange with 2.690.946 10/1954 Roehrl 206/204 holdmg 2.9l5.404 12/1959 T.1 v 312/3111 3.583.596 6/1971 229/43 15 Clam, 8 D'awmg U.S. Patent Nov.11,1975 SheetlofZ 3,918,578

US. Patent Nov. 11, 1975 Sheet 2 0f 2 DESICCANT END CAP The presentinvention relates to a desiccant end cap used for the purpose ofpreventing the flange on the end of a wave guide tube from beingsubjected to the effects of moisture.

By way of background, wave guides used in the electronic industry arefabricated by securing adjacent wave guide tubes to each other insubstantially perfect alignment. This securing is effected by placingadjacent flanges on the ends of adjacent tubes in a suitable fixture andthereafter welding the ends of the wave guide tubes to each other. Inorder to obtain substantially perfect alignment, the flanges havesurfaces thereon which are machined to very close tolerances and thesesurfaces are used as reference areas which are engaged by the fixtures.If the reference areas have scale, corrosion or rust thereon, perfectalignment cannot be effected and therefore the wave guide installationwill not function properly. Inaddition, if there is scale, corrosion orrust on the adjacent surfaces of the wave guide tubes which are to bewelded to each other, there is the possibility that improper joiningwill occur.

It is accordingly an important object of the present invention toprovide a desiccant end cap for mounting on the flange of a wave guideto protect all portions thereof from the effects of moisture andtherefore prevent the formation of scale, corrosion or rust.

Another object of the present invention is to provide a desiccant endcap which can be slipped on and off of the flange of a wave guide in anextremely simple and expedient manner and which, once installed, willremain securely in position until it is purposely removed.

Yet another object of the present invention is to provide a desiccantend cap for the flange of a wave guide which is fabricated in such amanner so that it provides a clearance space between certain portions ofthe end cap and the adjacent flange so as to permit unimpededcommunication between the desiccant carried by the end cap and thevarious surfaces of the flange.

A still further object of the present invention is to provide adesiccant end cap for a wave guide which is extremely simple inconstruction and highly reliable in operation. Other objects andattendant advantages of the present invention will readily be perceivedhereafter.

The present invention relates to a desiccant end cap for mounting on amember having a face portion and an outer portion extending transverselythereto comprising a cup-like member having an end portion, a rimextending from said end portion for overlying said outer portion of saidmember, desiccant container means mounted on said end portion, andspacer means for causing said end portion to be oriented in spacedrelationship to said face portion to permit communication between saiddesiccant container means and said face portion.

The various aspects of the present invention will be more fullyunderstood when the following portions of the specification are read inconjunction with the accompanying drawings wherein:

FIG. 1 is a fragmentary side elevational view of a wave guide mountingthe desiccant end caps of the present invention at its opposite endswith the end caps being covered by protective boots;

FIG. 2 is a fragmentary cross sectional view taken substantially alongline 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary cross sectional view similar to FIG. 2but with the desiccant cup also being in cross section;

FIG. 4 is a cross sectional view of the desiccant end cap takensubstantially along line 4-4 of FIG. 5;

FIG. 5 is a plan view of the desiccant end cap looking into the open endthereof;

FIG. 6 is a plan view of the desiccant end cap looking at the outer endthereof;

FIG. 7 is a cross sectional view of a modified type of end cap having animpermeable layer of material secured to the outer end thereof; and

FIG. 8 is a fragmentary cross sectional view ofa modifled form ofdesiccant container which may be substituted for the constructions shownin FIGS. 1-7.

The desiccant end cap 10 of the present invention is adapted to bemounted on flanges 11 which are located at the outer end portions ofwave guide tube 12. Protective boots 13, which form no part of thepresent invention, are fabricated from a suitable rubber-like plasticmaterial and are shrunk-fitted over flanges llhaving end caps 10installed thereon.

By way of background, steel flange 11 mounted on steel wave guide" tube12 includes aface 1'4 having an annular rib portion 15 extendingoutwardly from annular portion 16 which has an annular groove 17'therein. Annular rib 15 is flush with the end 17 of the wave guide tube12. Flange 11 also includes an annular surface 18 which is suitablyjoined to outer surface 19 of wave guide tube 12 which has a plasticliner 19' therein. In addition, flange 11. includes an outer annularsurface 20 which is machined to a very close tolerance as it is used'asa reference surface during the joining of adjacent flanges of adjacentwave guides, which must be in substantially perfect alignment. Thereforeit is mandatory that outer annular surface 20 be kept free of rust,scale, or any other form'of defacing corrosion which could alter itsdimensions in any respect, as such alterations could result in animproper alignment between adjacent wave guides. Furthermore, sincesurfaces 15 and 17 are placed in abutting engagement with like surfaceson an adjacent wave guide when they are joined, they must also be keptfree of rust, scale or corrosion, in order to insure their properalignment and their proper joining by a suitable welding process.

The improved end cap 10 of the present invention protects the end oftube 12, rib l4 and the critical surface 20 of flange 11 from corrosionand foreign matter which could be deposited thereon. End cap 10 includesa flexible body portion 21 in the form of a shallow cuplike memberhaving a circular substantially planar end portion or panel 22 with anintegral annular rim 23 extending substantially perpendicularly thereto.An outer flared lip 24 is formed at the open end of rim 23 for guidingcap 10 onto surface 20 of flange 11. The inner diameter of rim 23engages flange surface 20 with an interference fit so that it is mountedsnugly thereon. A plurality of dimples 25 are circumferentially spacedon the inner surface of rim 23 for engaging the rear side 26 of flange11 with a latching action to retain cap 10 securely in its installedposition. Because of the existence of dimples 25, if desired, rim 23need not provide an interference fit but can have an extremely close fitwhich is not an interference fit. Also, if desired, under certainconditions it may be permissible to rely only on the interference fit toretain cap 10 in its mounted position, in which event dimples 25 may beomitted. A cup 30, which contains a suitable desiccant 29, is centrallymounted on the inside surface 27 of end panel 22.

In the installed position of cap on flange 11, a clearance space 31 isprovided between the inside surface 27 of end portion 22 and theadjacent surfaces of rib 14 and tube end 17. This clearance space isprovided by dimples 28 which are circumferentially spaced on end portion21 and are located proximate rim 23. As can be seen from FIG. 3, exceptfor dimples 28, there is a clearance between all portions on the insideof end portion 22 and the outside of cup 30, on one hand, and theadjacent portions of flange 11 and the end 17 of tube 12, on the otherhand. This permits the effect of the desiccant 29 within cup 30 to beunrestrictedly communicated to clearance space 31 to thereby maintainthe end surface of flange 11 exposed to a continual drying action. Asnoted above, the only areas of contact between cap 10 and flange 11 areat rim 23 and at dimples 28. However, because of the fact that rim 23and dimples 28 are made out ofa material which is permeable, thedesiccating effect of desiccant 29 is also communicated through the rim23 to flange surface and through dimples 28 to the portions of surface16 under dimples 28. Bead silica gel has been found preferable for useas desiccant 29. However, other natural or synthetic desiccants such asgranular silica gel, molecular sieve in the form of granules, beads orpellets, montmorillonite, or calcium sulphate are also suitable.

Desiccant cup 30 includes an end wall 32 and a tapered side wall 33which merges into an annular flange 34 which is secured to surface 27,as by ultrasonic sealing, solvent welding, or suitable adhesive. Taperedside wall 33 aids in guiding cap 10 during installation. In thisparticular case container 30 is fabricated from cellulose acetatepropionate and cup member 21 is fabricated from cellulose acetatebutyrate, which is transparent. However, other materials may be used. Asnoted above, while the material from which cup member 21 is made ispermeable so that the absorbing effect of the desiccant can becommunicated to surface 20 and the portions of surface 16 against whichdimples 28 abut, it is less permeable than the material of cup 30 so asto restrict the transmittal of ambient moisture therethrough. As can beseen from FIG. 3, when end cap 10 is in position, it will protect thevarious covered and confined surfaces which must be protected. Inaddition, cap 10 may also be removed so as to permit access to theflange or the tube 12, as required. Thus, cap 10 not only provides adesiccating effect during long term storage but it also functions as ashort-term desiccant and a dust cover during the time that the waveguide is in the plant during fabrication.

A card 36 is positioned within cup 30 against surface 27 and is visiblethrough the transparent material from which cup member 21 is fabricatedso that the color of the cobalt chloride spot 37 may be compared withthe color of panel 38 for the purpose of determining the activity of thedesiccant in cup 30.

It is to be noted that there is a double layer of material, namely,flange 34 and end portion 21 opposite wave guide 17 so that thismaterial acts as a cushion to prevent marring of end surface 17 in theevent that the outer surface of end panel 21 is engaged by a foreignobject.

As can be seen from FIG. 2, when the protective boot 13 is shrunk intoplace, it deforms the flared lip 24, this being possible because of thefact that the plastic from which rim 23 is fabricated is flexible, asnoted above.

The wall thickness of cup 21 is 0.040 inches and the wall thickness ofcup 30 is 0.004 inches. Dimples 25 and 28 are hemispherical and have anouter radius of about 0.030 inches. The fact that cup 21 is relativelythick as compared to cup 30 also contributes to a slower rate ofpermeability through cup 21. If desired, the outside surface of endportion 22 of cup 21 may be painted with an impermeable paint to reduceits permeability.

In FIG. 7 an alternate embodiment of the present invention is disclosed.This embodiment which is designated l0 differs from the embodiments ofFIGS. l-6 in that cap member 40 is suitably formed of one piece ofmaterial so as to provide a tapered frustoconical cup portion 41, anannular front portion 42, and a rim 43. Rim 43 has dimples 25' which areanalogous to dimples 25 described above. In addition, dimples 28' areprovided which are analogous to dimples 28 described above. However, tocomplete the end cap, an impermeable transparent circular planar disc ofmaterial 44 is applied across the end of cap 10 and is attached toannular surface by any suitable means such as ultrasonic sealing,solvent welding, or a suitable adhesive. The fact that disc 44 isimpermeable cuts down on the exposure of the desiccant 45 to the areaoutside of tube 12. An indicator card 36', which is analogous toindicator card 36 of FIG. 8, is secured to the inside surface of disc44.

In FIG. 8 a still further embodiment of the present invention isdisclosed. This embodiment is essentially the same in all respects asthe embodiment of FIG. 7 except that the desiccant cup 41 includes aplurality of apertures 47 in the end surface 48 thereof and a porousretentive barrier, namely, a piece of felt 49 covers these apertures toprevent the desiccant 45 from falling out. With the construction of FIG.8 there is a greater permeability or an improved water vaportransmission rate through cup 41 than is obtainable with the cups ofFIGS. 1-7 which are not perforated.

It can thus be seen that the improved end caps of the present inventionis manifestly capable of achieving the above enumerated objects andwhile the preferred embodiments of the present invention have beendisclosed, it will be appreciated that the present invention is notlimited thereto but may be otherwise embodied within the scope of thefollowing claims.

What is claimed is:

l. A desiccant end cap for mounting on a member having a face portionand an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, and spacer means forproviding an effective clearance space between substantially said entireend portion and said face portion to permit effective communicationbetween said desiccant container means and substantially said entireface portion.

2. A desiccant end cap as set forth in claim 1. including securing meanson said rim for securing said end cap to said member.

3. A desiccant end cap as set forth in claim 1 wherein said rim includesan outwardly flared end portion for guiding said rim onto said outerportion of said member.

4. A desiccant end cap as set forth in claim 3 including securing meanson said rim for securing said end cap to said member.

5. A desiccant end cap as set forth in claim 4 wherein said securingmeans comprise spaced dimples extending inwardly from said rim.

6. A desiccant end cap as set forth in claim 1 wherein said end portionmerges into said desiccant container means which comprises a cup portionwhich is formed integrally with said end portion, and panel meanssecured across said end portion as a cover for said cup portion.

7. A desiccant end cap as set forth in claim 6 wherein said panel meansextends substantially entirely across said end portion and causes saidend portion to be relatively impermeable.

8. A desiccant end cap as set forth in claim 1 wherein said desiccantcontainer means comprises cup means on said end portion, desiccant meansin said cup means, aperture means in said cup means for increasing thepermeability of said cup means, and porous retentive barrier meanscovering said aperture means for preventing said desiccant means frompassing through said aperture means.

9. A desiccant end cap for mounting on a member having a face portionand an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, and spacer means forproviding a clearance space between said end portion and said faceportion to permit communication between said desiccant container meansand said face portion, said spacer means comprising spaced dimplesextending inwardly from said end portion toward said face portion.

10. A desiccant end cap as set forth in claim 9 wherein said desiccantcontainer means comprises cup means mounted on said end portion.

l1.'A desiccant end cap as set forth in claim 10 wherein said endportion is substantially planar.

12. A desiccant end cap for mounting on a member having a face portionand an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, spacer means for providinga clearance space between said end portion and said face portion topermit communication between said desiccant container means and saidface portion, securing means on said rim for securing said end cap tosaid member, said securing means comprising first spaced dimplesextending inwardly from said rim, and said spacer means comprisingsecond spaced dimples extending inwardly from said end portion towardsaid face portion.

13. A desiccant end cap as set forth in claim 12 wherein said desiccantcontainer means comprises cup means mounted on said end portion.

14. A desiccant end cap for mounting on a member having a face portionand an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, and spacer means forproviding a clearance space between said end portion and said faceportion to permit communication between said desiccant container meansand said face portion, said rim being permeable and of a size to engagesaid outer portion of said member, whereby the effect of said desiccantis communicated to said outer portion through said clearance space andthrough said permeable rim.

15. A desiccant end cap as set forth in claim 14 wherein said rim is ofa size to engage said outer portion with an interference fit.

1. A desiccant end cap for mounting on a member having a face portionand an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, and spacer means forproviding an effective clearance space between substantially said entireend portion and said face portion to permit effective communicationbetween said desiccant container means and substantially said entireface portion.
 2. A desiccant end cap as set forth in claim 1 includingsecuring means on said rim for securing said end cap to said member. 3.A desiccant end cap as set forth in claim 1 wherein said rim includes anoutwardly flared end portion for guiding said rim onto said outerportion of said member.
 4. A desiccant end cap as set forth in claim 3including securing means on said rim for securing said end cap to saidmember.
 5. A desiccant end cap as set forth in claim 4 wherein saidsecuring means comprise spaced dimples extending inwardly from said rim.6. A desiccant end cap as set forth in claim 1 wherein said end portionmerges into said desiccant container means which comprises a cup portionwhich is formed integrally with said end portion, and panel meanssecured across said end portion as a cover for said cup portion.
 7. Adesiccant end cap as set forth in claim 6 wherein said panel meansextends substantially entirely across said end portion and causes saidend portion to be relatively impermeable.
 8. A desiccant end cap as setforth in claim 1 wherein said desiccant container means comprises cupmeans on said end portion, desiccant means in said cup mEans, aperturemeans in said cup means for increasing the permeability of said cupmeans, and porous retentive barrier means covering said aperture meansfor preventing said desiccant means from passing through said aperturemeans.
 9. A desiccant end cap for mounting on a member having a faceportion and an outer portion extending transversely thereto comprising acup-like member having an end portion, a rim extending from said endportion for overlying said outer portion of said member, desiccantcontainer means mounted on said end portion, and spacer means forproviding a clearance space between said end portion and said faceportion to permit communication between said desiccant container meansand said face portion, said spacer means comprising spaced dimplesextending inwardly from said end portion toward said face portion.
 10. Adesiccant end cap as set forth in claim 9 wherein said desiccantcontainer means comprises cup means mounted on said end portion.
 11. Adesiccant end cap as set forth in claim 10 wherein said end portion issubstantially planar.
 12. A desiccant end cap for mounting on a memberhaving a face portion and an outer portion extending transverselythereto comprising a cup-like member having an end portion, a rimextending from said end portion for overlying said outer portion of saidmember, desiccant container means mounted on said end portion, spacermeans for providing a clearance space between said end portion and saidface portion to permit communication between said desiccant containermeans and said face portion, securing means on said rim for securingsaid end cap to said member, said securing means comprising first spaceddimples extending inwardly from said rim, and said spacer meanscomprising second spaced dimples extending inwardly from said endportion toward said face portion.
 13. A desiccant end cap as set forthin claim 12 wherein said desiccant container means comprises cup meansmounted on said end portion.
 14. A desiccant end cap for mounting on amember having a face portion and an outer portion extending transverselythereto comprising a cup-like member having an end portion, a rimextending from said end portion for overlying said outer portion of saidmember, desiccant container means mounted on said end portion, andspacer means for providing a clearance space between said end portionand said face portion to permit communication between said desiccantcontainer means and said face portion, said rim being permeable and of asize to engage said outer portion of said member, whereby the effect ofsaid desiccant is communicated to said outer portion through saidclearance space and through said permeable rim.
 15. A desiccant end capas set forth in claim 14 wherein said rim is of a size to engage saidouter portion with an interference fit.